Ester intermediates for 2-benzoyl-4-phenyl-1,3-cyclohexanediones

ABSTRACT

Compounds of the formula ##STR1## wherein R is halogen; C 1  -C 2  alkyl; C 1  -C 2  alkoxy; trifluoromethoxy or difluoromethoxy; nitro; cyano; C 1  -C 2  haloalkyl; R a  SO n  --wherein n is 0 or 2 and R a  is C 1  -C 2  alkyl, trifluoromethyl or difluoromethyl; 
     R 1  is hydrogen or C 1  -C 4  alkyl; 
     R 2  is hydrogen or C 1  -C 4  alkyl; or 
     R 1  and R 2  together are C 2  -C 5  alkylene; 
     R 3  is hydrogen or C 1  -C 4  alkyl; 
     R 4  is hydrogen or C 1  -C 4  alkyl; or 
     R 3  and R 4  together are C 2  -C 5  alkylene; 
     R 5 , R 6 , R 7  and R 8  independently are (1) hydrogen; (2) halogen; (3) C 1  -C 4  alkyl; (4) C 1  -C 4  alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C 1  -C 4  haloalkyl; (9) R b  SO n  --wherein n is the integer 0, 1 or 2; and R b  is (a) C 1  -C 4  alkyl; (b) C 1  -C 4  alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR c  R d  wherein R c  and R d  independently are hydrogen or C 1  -C 4  alkyl; (11) R e  C(O)--wherein R e  is C 1  -C 4  alkyl or C 1  -C 4  alkoxy; or (12) --SO 2  NR c  R d  wherein R c  and R d  are as defined; and (13) --N(R c )C(O)R d  wherein R c  and R d  are as defined; and 
     R 9  is hydrogen or C 1  -C 4  alkyl, and their salts.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 906,462, filed Sept. 12, 1986, now U.S. Pat. No. 4,795,488.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,350,705 relates to certain antihypertensive compounds that can have the following structural formula ##STR2## wherein R¹ is unsubstituted or substituted phenyl; M is --(CH₂)_(m) in which m is the integer 0-4; and X, Y and Z are hydrogen, lower alkyl, lower alkoxy, lower alkylcarbonyloxy, hydroxy, lower alkylsulfonyl, nitro, cyano or halogen. Specifically taught are 2-benzoyl-5-phenyl-cyclohexane-1,3-dione and 2-(4-chlorobenzoyl)-5-phenylcyclohexane-1,3-dione.

DESCRIPTION OF THE INVENTION

This invention relates to 2-(substituted benzoyl)-4-(substituted or unsubstituted phenyl)-1,3-cyclohexanediones and their use as herbicides.

One embodiment of this invention is an herbicidal composition comprising an herbicidally active 2-(substituted benzoyl)-4-(substituted or unsubstituted phenyl)-1,3-cyclohexanedione and an inert carrier therefor. The 5- and 6-positions of the 1,3-cyclohexanedione moiety are preferably substituted with groups hereinafter defined, most preferably with hydrogen or methyl groups. The benzoyl and phenyl moieties can be substituted, preferably with the groups hereinafter recited.

Also embodied within the scope of this invention are novel compounds having the following structural formula ##STR3## wherein R is halogen; C₁ -C₂ alkyl, preferably methyl; C₁ -C₂ alkoxy, preferably methoxy, trifluoromethoxy or difluoromethoxy; nitro; cyano; C₁ -C₂ haloalkyl, preferably trifluoromethyl; R^(a) SO_(n) -- wherein n is 0 or 2, preferably 2 and R^(a) is C₁ -C₂ alkyl, preferably methyl, trifluoromethyl or difluoromethyl. Preferably, R is chlorine, bromine, C₁ -C₂ alkyl, C₁ -C₂ alkoxy, trifluoromethyl, cyano, nitro, C₁ -C₂ alkylthio or C₁ -C₂ alkylsulfonyl; more preferably chlorine, nitro, methyl, trifluoromethyl or methylsulfonyl; and

R¹ is hudrogen or C₁ -C₄ alkyl, preferably methyl;

R² is hydrogen or C₁ -C₄ alkyl, preferably methyl; or

R¹ and R² together are C₂ -C₅ alkylene;

R³ is hydrogen or C₁ -C₄ alkyl, preferably methyl;

R⁴ is hydrogen or C₁ -C₄ alkyl, preferably methyl; or

R³ and R⁴ together are C₂ -C₅ alkylene;

R⁵, R⁶, R⁷ and R⁸ independently are (1) hydrogen; (2) halogen, preferably chlorine, fluorine or bromine; (3) C₁ -C₄ alkyl, preferably methyl; (4) C₁ -C₄ alkoxy, preferably methoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl, more preferably trifluoromethyl; (9) R^(b) SO_(n) --wherein n is the integer 0, 1 or 2, preferably 2; and R^(b) is (a) C₁ -C₄ alkyl, preferably methyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano, preferably chloromethyl, trifluoromethyl or cyanomethyl; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)--wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; (12)--SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or (13)--N(R^(c))C(O)R^(d) wherein R^(e) and R^(d) are as defined; and

R⁹ is hydrogen or C₁ -C₄ alkyl.

Preferably R⁵ is in the 3-position. More preferably R⁵ and R⁷ are hydrogen, chlorine, fluorine, trifluoromethyl, cyano, C₁ -C₄ alkoxy or C₁ -C₄ thioalkyl. Most preferably, R⁵ and R⁷ are hydrogen. Preferably R⁶ and R⁸ are in the 4-position. Most preferably R⁶ and R⁸ are halogen, cyano, trifluoromethyl, or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl, preferably methyl or C₁ -C₄ haloalkyl, preferably chloromethyl, difluoromethyl or trifluoromethyl.

The term "C₁ -C₄ alkyl" includes methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and t-butyl. The term "halogen" includes chlorine, bromine, iodine and fluorine. The terms "C₁ -C₄ alkoxy" includes methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy and t-butoxy. The term "C₁ -C₄ haloalkyl" includes the alkyl groups defined above under C₁ -C₄ alkyl in which one or more hydrogens is replaced by chlorine, bromine, iodine or fluorine.

Salts of the above-described compounds (as defined hereinafter) are included within the scope of the instant invention.

The compounds of this invention can have the following four structural formulae because of tautomerism: ##STR4## wherein R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ are as defined above.

The circled proton on each of the four tautomers is reasonably labile. These protons are acidic and can be removed by reaction with a base to form a salt having an anion of the following four resonance forms: ##STR5## wherein R, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ are as defined above.

Examples of cations of these bases are inorganic cations such as alkali metals, e.g. lithium, sodium and potassium; the alkaline earth metals, e.g. calcium and magnesium or ammonium or organic cations such as substituted ammonium, sulfonium, sulfoxonium or phosphonium wherein the substituents are aliphatic or aromatic groups.

Those skilled in the art will recognize in considering the salts of this invention that varying degrees of association between the anion and cation will exist depending upon the nature of the cation. In some instances with a suitable cation, such as copper, the salt can exist in a chelated form.

The compounds of this invention and their salts are active herbicides of a general type. That is, they are herbicidally effective against a wide range of plant species. The method of controlling undesirable vegetation of the present invention comprises applying an herbicidally effective amount of the above-described compounds or their salts to the area where control is desired.

The compounds of the present invention can be prepared by the following two-step general method.

The process proceeds via the production of an enol ester intermediate as shown in reaction (1). The final product is obtained by rearrangement of the enol ester as shown in reaction (2).

The process is conducted in the presence of a catalytic amount of a source of cyanide anion and/or hydrogen cyanide, together with a molar excess, with respect to the enol ester, of a moderate base.

The two reactions may be conducted as separate steps by isolation and recovery of the enol ester using conventional techniques prior to conducting step (2), or by addition of a cyanide source to the reaction medium after the formation of the enol ester, or in one step by inclusion of the cyanide source at the start of reaction (1). ##STR6## wherein R through R⁹ and moderate base are as defined and X is halogen, preferably chlorine, C₁ -C₄ alkyl--C(O)--O--, C₁ -C₄ alkoxy-C(O)--O-- or ##STR7## wherein R, R⁵ and R⁶ in this portion of the molecule are identical with those in the reactant shown above and the moderate base is as defined, preferably tri-C₁ -C₆ alkylamine, alkali metal carbonate or alkali metal phosphate.

Generally, in step (1) mole amounts of the dione and substituted benzoyl reactant are used, along with a mole amount or excess of the base. The two reactants are combined in an organic solvent such as methylene chloride, toluene, ethyl acetate or dimethylformamide. The base or benzoyl reactant preferably is added to the reaction mixture with cooling. The mixture is stirred at 0° C.-50° C. until the reaction is substantially complete. ##STR8## wherein the moderate base and R through R⁹ are as defined above.

Generally, in step (2) a mole of the enol ester intermediate is reacted with 1 to 4 moles of the moderate base, preferably about 2 moles of moderate base and from 0.01 mole to about 0.5 mole or higher, preferably about 0.01-0.1 mole of the cyanide source. The mixture is stirred in a reaction pot until the rearrangement is substantially complete at a temperature below 50° C., preferably about 20° C. to about 40° C., and the desired product is recovered by conventional techniques.

The term "cyanide source" refers to a substance or substances which under the rearrangement conditions consists of or generates hydrogen cyanide and/or cyanide anion.

Preferred cyanide sources are alkali metal cyanides such as sodium and potassium cyanide; cyanohydrins of methyl alkyl ketones having from 1-4 carbon atoms in the alkyl groups, such as acetone or methyl isobutyl ketone cyanohydrins; benzaldehyde cyanohydrin; cyanohydrins of C₂ -C₅ aliphatic aldehydes such as acetaldehyde cyanohydrin, propionaldehyde propionaldehyde cyanohydrin, etc.; cyclohexanone cyanohydrin; lactonitrile; zinc cyanide; di- and tri-(lower alkyl) silyl cyanides, notably dimethyl- and trimethyl-silyl cyanide; potassium ferric cyanide; and hydrogen cyanide itself. Hydrogen cyanide is considered most advantageous as it produces relatively rapid reaction and is inexpensive. Among cyanohydrins the preferred cyanide source is acetone cyanohydrin.

The cyanide source is used in an amount up to about 50 mole percent based on the enol ester. It may be used in as little as about 1 mole percent to produce an acceptable rate of reaction at about 40° C. on a small scale. Larger scale reactions give more reproducible results with slightly higher catalyst levels of about 2 mole percent. Generally about 1-10 mole % of the cyanide source is preferred.

The process is conducted with a molar excess, with respect to the enol ester, of a moderate base. By the term "moderate base" is meant a substance which acts as a base yet whose strength or activity as a base lies between that of strong bases such as hydroxides (which could cause hydrolysis of the enol ester) and that of weak bases such as N,N-dimethylaniline (which would not function effectively). Moderate bases suitable for use in this embodiment include both organic bases, e.g., trialkylamines such as triethylamine and inorganic bases such as alkali metal carbonates and phosphates. Suitable inorganic bases include potassium carbonate and trisodium phosphate.

The base is used in an amount of from about 1 to about 4 moles per mole of enol ester, preferably about 2 moles per mole.

When the cyanide source is an alkali metal cyanide, particularly potassium cyanide, a phase transfer catalyst may be included in the reaction. Particularly suitable phase transfer catalysts are the crown ethers.

A number of different solvents are useful in this process, depending on the nature of the acid halide or the acylated product. A preferred solvent for this reaction is 1,2-dichloroethane. Other solvents which may be employed, depending on the reactants or products include toluene, acetonitrile, methylene chloride, ethyl acetate, dimethylformamide, and methyl isobutyl ketone (MIBK).

In general, depending on the nature of the reactants and the cyanide source, the rearrangement may be conducted at temperatures up to about 50° C.

The above described substituted benzoyl chlorides can be prepared from the corresponding substituted benzoic acids according to the teaching of Reagents for Organic Synthesis, Vol. I. L. F. Fieser and M. Fieser, pp. 767-769 (1967). ##STR9## wherein R, R⁵ and R⁶ are as previously defined.

The substituted benzoic acids can be prepared by a wide variety of general methods according to the teaching of The Chemistry of Carboxylic Acids and Esters, S. Patai, editor, J. Wiley and Sons, New York, N.Y. (1969) and Survey of Organic Synthesis, C. A. Buehler and D. F. Pearson, J. Wiley and Sons, (1970).

The following are three representative examples of the methods described therein. ##STR10## wherein R, R⁵ and R⁶ are as previously defined.

In reaction (a) the substituted benzonitrile is heated to reflux in aqueous sulfuric acid for several hours. The mixture is cooled and the reaction product is isolated by conventional techniques. ##STR11## wherein R, R⁵ and R⁶ are as previously defined.

In reaction (b) the substituted acetophenone is heated to reflux for several hours in an aqueous hypochlorite solution. The mixture is cooled and the reaction product is isolated by conventional techniques. ##STR12## wherein R, R⁵ and R⁶ are as previously defined.

In reaction (c) the substituted toluene is heated to reflux in an aqueous solution of potassium permanganate for several hours. The solution is then filtered and the reaction product is isolated by conventional techniques.

The above-described substituted cyclohexane-1,3-diones can be prepared according to the teaching of E. D. Bergmann and J. Szmuszkovicz, J. Amer. Chem. Soc., 875, 3226 (1953).

The following example teaches the synthesis of a representative compound of this invention.

EXAMPLE 1 4-(2-Fluorophenyl)-2-(2-trifluoromethylbenzoyl)-cyclohexane-1,3-dione ##STR13##

2-Trifluoromethylbenzoyl chloride (7.1 g, 0.034 mole) and 4-(2-fluorophenyl)-1,3-cyclohexanedione (7.0 g, 0.034 mole) were dissolved in methylene chloride. Triethylamine (4.1 g, 0.041 mole) was added dropwise and the resulting solution stirred for one hour. The solution was washed with 2 normal hydrochloric acid (2N HCl), 5% potassium carbonate solution, and saturated sodium chloride solution, dried over anhydrous magnesium sulfate (MgSO₄) and concentrated under vacuum. The residue ws dissolved in 40 ml of acetonitrile. Triethylamine (1 equivalent) and acetone cyanohydrin (0.4 ml) were added and the solution stirred for 1 hour at room temperature. After dilution with ether (150 ml), the solution was washed with 2N HCl. The ether layer was then stirred with 100 ml of 5% copper (II) acetate. The resulting copper salt was filtered, washed with hexane, and stirred with 6N hydrochloric acid to destroy the salt. the acidic aqueous solution was extracted with ether. The ether solution was then washed with water and dried over MgSO₄. Concentration of the ether solution under vacuum afforded 4.4 g of the desired product as a brown oil (34.2% yield). The structure was confirmed by instrumental analysis.

The following is a table of certain selected compounds that are preparable according to the procedure described hereto. Compound numbers are assigned to each compound and are used throughout the remainder of the application.

                                      TABLE I                                      __________________________________________________________________________      ##STR14##                                                                     Cmpd.                                                                          No. R  R.sup.1                                                                           R.sup.2                                                                          R.sup.3                                                                           R.sup.4                                                                          R.sup.5                                                                           R.sup.6                                                                              R.sup.7                                                                             R.sup.8                                                                             R.sup.9                                                                           m.p. °C.                         __________________________________________________________________________     1   Cl H  H H  H H  4-Cl  H    H    H  139-140                                 2   Cl H  H H  H H  4-SO.sub.2 Me                                                                        H    3-CF.sub.3                                                                          H  glass                                   3   NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           H    3-CF.sub.3                                                                          H  oil                                     4   Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-F  H    H  oil                                     5.sup.a                                                                            CF.sub.3                                                                          H  H H  H H  H     2-F  H    H  oil                                     6   Cl H  H H  H H  4-Cl  2-F  H    H  oil                                     7   Cl H  H H  H H  4-Cl  H    4-F  H  oil                                     8   CH.sub.3                                                                          H  H H  H H  4-SO.sub.2 Et                                                                        2-F  H    H  glass                                   9   CH.sub.3                                                                          H  H H  H H  4-SO.sub.2 Et                                                                        H    4-F  H  oil                                     10  Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-Cl H    H  glass                                   11  Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-MeO                                                                               H    H  135-140                                 12  Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-F  6-Cl H  94-98                                   13  Cl H  H H  H H  4-SO.sub.2 Me                                                                        H    4-MeO                                                                               H  glass                                   14  Cl H  H Me H H  4-SO.sub.2 Me                                                                        2-F  H    H  glass                                   15  Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-F  H    Me glass                                   16  Cl Me H H  H H  4-SO.sub.2 Me                                                                        2-F  H    H  75-80                                   17  NO.sub.2                                                                          H  H H  H H  4-Cl  2-F  H    Me oil                                     18  NO.sub.2                                                                          H  H H  H H  4-Cl  H    4-F  H  oil                                     19  NO.sub.2                                                                          H  H H  H H  4-Cl  H    3-CF.sub.3                                                                          H  oil                                     20  NO.sub.2                                                                          H  H Me H H  4-Cl  2-F  H    H  glass                                   21  NO.sub.2                                                                          H  H H  H H  4-Cl  2-F  6-Cl H  glass                                   22  NO.sub.2                                                                          Me H H  H H  4-Cl  2-F  H    H  oil                                     23  NO.sub.2                                                                          H  H H  H H  4-Cl  2-Cl H    H  172-175                                 24  Cl H  H H  H H  4-SO.sub.2 Me                                                                        H    H    H  oil                                     25  Cl H  H Me H H  4-SO.sub.2 Me                                                                        H    H    H  oil                                     26  CH.sub.3                                                                          H  H H  H H  4-SO.sub.2 Et                                                                        2-F  H    Me oil                                     27  Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-F  6-Cl Me oil                                     28  Cl H  H Me H H  4-SO.sub.2 Me                                                                        H    H    Me oil                                     29  Cl H  H H  H H  4-SO.sub.2 Me                                                                        H    H    Me oil                                     30  NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           2-F  H    Me oil                                     31  NO.sub.2                                                                          H  H H  H H  4-Cl  H    H    H  oil                                     32  NO.sub.2                                                                          H  H Me H H  4-Cl  H    H    H  oil                                     33  Cl H  H H  H H  4-SO.sub.2 Me                                                                        2-Cl 4-Cl H  oil                                     34  NO.sub.2                                                                          H  H Me H H  4-Cl  H    H    Me oil                                     35  NO.sub.2                                                                          H  H H  H H  4-Cl  H    H    Me oil                                     36  Cl H  H H  H 3-Cl                                                                              4-SO.sub.2 Et                                                                        2-F  H    Me wax                                     37  NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           H    H    H  oil                                     38  NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           2-F  H    H  oil                                     39  Cl Me H H  H H  4-SO.sub.2 Me                                                                        2-F  H    Me oil                                     40  NO.sub.2                                                                          H  H H  H H  4-Cl  2-F  H    H  oil                                     41  NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           H    4-F  H  oil                                     42  NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           2-F  6-Cl H  oil                                     43  NO.sub.2                                                                          H  H H  H H  4-CF.sub.3                                                                           2-NO.sub.2                                                                          H    H  oil                                     __________________________________________________________________________      .sup.a Prepared in Example I.                                            

Herbicidal Screening Tests

As previously mentioned, the herein described compounds produced in the above-described manner are phytotoxic compounds which are useful and valuable in controlling various plant species. Selected compounds of this invention were tested as herbicides in the following manner.

Pre-emergence herbicide test. On the day preceding treatment, seeds of seven different weed species are planted in loamy sand soil in individual rows using one species per row across the width of a flat. The seeds used are green foxtail (FT) (Setaria viridis), watergrass (WG) (Echinochloa crusgalli), wild oat (WO) (Avena fatua), annual morningglory (AMG) (Ipomoea lacunosa), velvetleaf (VL) (Abutilon theophrasti), Indian mustard (MD) (Brassica juncea), and yellow nutsedge (YNG) (Cyperus esculentus). Ample seeds are planted to give about 20 to 40 seedlings per row, after emergence, depending upon the size of the plants.

Using an analytical balance, 600 milligrams (mg) of the compound to be tested are weighed out on a piece of glassine weighing paper. The paper and compound are placed in a 60 milliliter (ml) wide-mouth clear bottle and dissolved in 45 ml of acetone or substituted solvent. Eighteen ml of this solution are transferred to a 60 ml wide-mouth clear bottle and diluted with 22 ml of a water and acetone mixture (19:1) containing enough polyoxyethylene sorbitan monolaurate emulsifier to give a final solution of 0.5% (v/v). The solution is then sprayed on a seeded flat on a linear spray table calibrated to deliver 80 gallons per acre (748 L/ha). The application rate is 4 lb/acre (4.48 Kg/ha).

After treatment, the flats are placed in the greenhouse at a temperature of 70° to 80° F. and watered by sprinkling. Two weeks after treatment, the degree of injury or control is determined by comparison with untreated check plants of the same age. The injury rating from 0 to 100% is recorded for each species as percent control with 0% representing no injury and 100% representing complete control.

The results of the tests are shown in the following Table II.

                  TABLE II                                                         ______________________________________                                         Pre-Emergence Herbicidal Activity                                              Aplication Rate - 4.48 kg/ha                                                   Cmpd.                                                                          No.   FT      WG     WO    AMG   VL    MD    YNG                               ______________________________________                                         1     0       20     10    5     0     0     60                                2     0       75     60    80    95    100   70                                3     0       0      5     10    80    90    0                                 4     95      100    90    100   100   100   80                                5     10      5      20    5     40    90    --                                6     0       10     10    40    100   100   60                                7     0       0      10    40    100   100   80                                8     30      100    85    95    100   100   80                                9     20      100    80    90    100   100   80                                10    85      100    80    80    100   100   80                                11    0       100    5     0     10    100   --                                12    100     100    10    50    100   100   80                                13    40      100    10    30    100   100   80                                14    100     100    80    100   100   100   80                                15    30      95     80    95    100   100   80                                16    90      100    30    100   100   100   80                                17    95      100    70    100   100   100   80                                18    100     100    70    100   100   100   80                                19    10      0      0     30    100   100   0                                 20    50      80     40    100   100   100   75                                21    100     80     50    100   100   100   75                                22    10      85     40    100   100   100   70                                23    100     95     90    30    100   100   30                                24    100     100    90    100   100   100   80                                25    20      90     40    85    90    100   80                                26    0       70     30    90    100   100   80                                27    100     100    60    100   100   100   80                                28    0       80     10    90    100   100   80                                29    80      100    95    100   100   100   80                                30    100     10     90    100   100   100   80                                31    100     100    100   100   100   100   80                                32    100     100    20    100   100   100   80                                33    100     100    85    75    100   100   70                                34    100     100    10    100   100   100   80                                35    100     100    50    100   100   100   80                                36    100     100    90    100   100   100   80                                37    100     100    80    100   100   100   80                                38    100     100    100   100   100   100   80                                39    100     100    40    100   100   100   80                                40    100     100    100   100   100   100   80                                41    100     95     80    100   100   100   80                                42    100     95     40    100   100   100   80                                43    100     100    40    60    100   100   80                                ______________________________________                                          A dash (--) indicates that the weed was not tested.                      

Post-Emergence Herbicide Test: This test is conducted in an identical manner to the testing procedure for the pre-emergence hericide test, except the seeds of the seven different weed species are planted 10-12 days before treatment. Also, watering of the treated flats is confined to the soil surface and not to the foliage of the sprouted plants.

The results of the post-emergence herbicide test are reported in Table III.

                  TABLE III                                                        ______________________________________                                         Post-Emergence Herbicidal Activity                                             Application Rate - 4.48 kg/ha                                                  Cmpd.                                                                          No.   FT      WG     WO    AMG   VL    MD    YNG                               ______________________________________                                         1     20      60     40    60    60    50    80                                2     20      75     70    80    90    85    30                                3     30      10     10    50    85    85    0                                 4     100     50     50    50    80    80    30                                5     0       5      30    10    20    50    0                                 6     10      0      0     50    80    70    10                                7     70      0      0     50    80    100   60                                8     80      50     50    60    60    80    30                                9     20      60     50    60    60    90    50                                10    100     95     80    30    60    60    80                                11    0       50     5     10    5     30    30                                12    85      85     50    60    70    65    80                                13    80      80     50    50    70    65    70                                14    90      100    90    90    100   100   30                                15    30      80     80    100   100   100   60                                16    60      85     85    90    100   95    30                                17    100     100    80    100   100   100   60                                18    70      100    90    90    100   100   80                                19    10      30     30    90    95    100   0                                 20    30      40     70    80    90    100   30                                21    80      80     60    90    80    100   30                                22    50      60     50    90    90    100   30                                23    20      50     50    100   90    100   70                                24    70      80     80    80    80    90    70                                25    10      40     40    60    80    80    30                                26    20      50     40    60    80    60    30                                27    80      80     60    65    80    80    70                                28    30      50     40    80    80    80    30                                29    30      60     40    80    80    80    30                                30    60      80     50    80    80    80    30                                31    85      100    60    100   100   100   80                                32    30      85     20    90    85    100   70                                33    90      80     60    60    80    80    30                                34    80      85     20    90    90    100   30                                35    30      100    30    100   100   100   80                                36    10      90     20    80    95    95    10                                37    30      90     50    80    80    90    30                                38    85      85     60    80    80    80    30                                39    10      60     40    50    60    60    30                                40    50      80     50    80    90    80    80                                41    0       80     50    80    80    80    70                                42    80      90     60    80    80    90    60                                43    30      80     20    80    90    90    60                                ______________________________________                                          A dash (--) indicates that the weed was not tested.                      

The compounds of the present invention and their salts are useful as herbicides and can be applied in a variety of ways at various concentrations.In practice, the compounds or salts are formulated into herbicidal compositions, by admixture, in herbicidally effective amounts, with the adjuvants and carriers normally employed for facilitating the dispersion of active ingredients for agricultural applications, recognizing the fact that the formulation and mode of application of a toxicant may affect the activity of the materials in a given application. Thus, these active herbicidal compounds or salts can be formulated as granules of relatively large particle size, as wettable powders, as emulsifiable concentrates, as powdery dusts, as flowables, as solutions or as any of several other known types of formulations, depending upon the desired mode of application. These formulations may contain as little as about 0.5% to as much as about 95% or more by weight of active ingredient. A herbicidally effective amount depends upon the nature of the seeds or plants to be controlled and the rate of application varies from about 0.01 to approximately 10 pounds per acre, preferably from about 0.02 to about 4 pounds per acre.

Wettable powders are in the form of finely divided particles which disperse readily in water or other dispersants. The wettable powder is ultimately applied to the soil either as a dry dust or as a dispersion in water or other liquid. Typical carriers for wettable powders include fuller's earth, kaolin clays, silicas and other readily wet organic or inorganic diluents. Wettable powders normally are prepared to contain about 5% to about 95% of the active ingredient and usually also contain a small amount of wetting, dispersing, or emulsifying agent to facilitate wetting and dispersion.

Emulsifiable concentrates are homogeneous liquid compositions which are dispersible in water or other dispersant, and may consist entirely of the active compound or salt with a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthal, isophorone and other non-volatile organic solvents. For herbicidal application, these concentrates are dispersed in water or other liquid carrier and normally applied as a spray to the area to be treated. The percentage by weight of the essential active ingredient may vary according to the manner in which the composition is to be applied, but in general comprises about 0.5% to 95% of active ingredient by weight of the herbicidal composition.

Granular formulations wherein the toxicant is carried on relatively coarse particles, are usually applied without dilution to the area in which suppression of vegetation is desired. Typical carriers for granular formulations include sand, fuller's earth, attapulgite clay, bentonite clays, montmorillonite clay, vermiculite, perlite and other organic or inorganic materials which absorb or which may be coated with the toxicant. Granular formulations normally are prepared to contain about 5% to about 25% of active ingredients which may include surface-active agents such heavy aromatic naphthas, kerosene or other petroleum fractions, or vegetable oils; and/or stickers such as destrins, glue or synthetic resins.

Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their salts; polyhydric alcohols; polyethoxylated alcohols; esters and fatty amines; and other types of surface-active agents, many of which are available in commerce. The surface-active agent, when used, normally comprises from 0.1% to 15% by weight of the herbicidal composition.

Dusts, which are free-flowing admixtures of the active ingredient with finely divided solids such as talc, clays, flours and other organic and inorganic solids which act as dispersants and carriers for the toxicant, are useful formulations for soli-incorporating application.

Pastes, which are homogeneous suspensions of a finely divided solid toxicant in a liquid carrier such as water or oil, are employed for specific purposes. These formulations normally contain about 5% to about 95% of active ingredient by weight, and may also contain small amounts of a wetting, dispersing or emulsifying agent to facilitate dispersion. For application, the pastes are normally diluted and applied as a spray to the area to be affected.

Other useful formulations for herbicidal applications include simple solutions of the active ingredient in a dispersant in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene and other organic solvents. Pressurized sprays, typically aerosols, wherein the active ingredient is dispersed in finely-divided form as a result of vaporization of a low boiling dispersant solvent carrier, such as the Freons, may also be used.

The phytotoxic compositions of this invention can be applied to the plants in the conventional manner. Thus, the dust and liquid compositions can be applied to the plant by the use of power-dusters, boom and hand sprayers and spray dusters. The compositions can also be applied from airplanes as a dust or a spray or by rope wick applications because they are effective in very low dosages. In order to modify or control growth of germinating seeds or emerging seedlings, as a typical example, the dust and liquid compositions can be applied to the soil according to conventional methods and can be distributed in the soil to a depth of at least 1/2 inch below the soil surface. It is not necessry that the phytotoxic compositions be mechanically admixed with the soil particles since these compositions can also be applied merely by spraying or sprinkling the surface of the soil. The phytotoxic compositions of this invention can also be applied by addition to irrigation water supplied to the field to be treated. This method of application permits the penetration of the compositions into the soil as the water is absorbed therein. Dust compositions, granular compositions or liquid formulations applied to the surfce of the soil can be distributed below the surface of the soil by conventional means such as discing, dragging or mixing operations. In the following examples the herbicidal compound can be substituted with the herbicidal salt of the compound.

    __________________________________________________________________________     Gerneral Formula with Ranges                                                                        Specific Formula                                          __________________________________________________________________________     EMULSIFIABLE CONCENTRATE FORMULATIONS                                          Herbicidal compound                                                                           5-55  herbicidal compound                                                                          24                                          surfactant(s)  5-25  proprietary blend of oil-                                                                    10                                          solvent(s)     20-90 soluble sulfonates and                                                   100%  polyoxyethylene ethers                                                         polar solvent 27                                                               petroleum hydrocarbon                                                                        39                                                                             100%                                        WETTABLE POWDER FORMULATIONS                                                   herbicidal compound                                                                           3-90  herbicidal compound                                                                          80                                          wetting agent  0.5-2 sodium dialkyl naphthalene                                                                   0.5                                         dispersing agent                                                                              1-8   sulfonate                                                 diluent(s)     8.5-87                                                                               sodium lignosulfonate                                                                        7                                                          100%  attapulgite clay                                                                             12.5                                                                           100%                                        EXTRUDED GRANULAR FORMULATI0NS                                                 herbicidal compound                                                                           1-20  herbicidal compound                                                                          10                                          binding agent  0-10  lignin sulfonate                                                                             5                                           diluent(s)     70-99 calcium carbonate                                                                            85                                                         100%                100%                                        FLOWABLE FORMULATIONS                                                          herbicidal compound                                                                           20-70 herbicidal compound                                                                          45                                          surfactant(s)  1 -10 polyoxyethylene ether                                                                        5                                           suspending agent(s)                                                                           0.05-1                                                                               attagel       0.05                                        antifreeze agent                                                                              1-10  propylene glycol                                                                             10                                          antimicrobial agent                                                                           1-10  1,2-benzisothiazoline-3-one                                                                  0.03                                        antifoam agent 0.1-1 silicone defoaer                                                                             0.02                                        solvent        7.95-77.85                                                                           water         39.9                                                       100%                100%                                        __________________________________________________________________________

When salts are used as the active ingredient in the herbicidal compositions of this invention it is recommended to use salts that are agriculturally acceptable.

The phytotoxic compositions of this invention can also contain other additives, for example, fertilizers, other herbicides and other pesticides, used as adjuvant or in combination with any of the above-described adjuvants. Fertilizers useful in combination with the active ingredients include, for example, ammonium nitrate, urea and superphosphate. 

What is claimed is:
 1. An intermediate compound of the structural formula ##STR15## wherein R is chlorine, bromine, methyl, methoxy nitro; trifluoromethyl or methylsulfonyl;R¹ is hydrogen or methyl; R² is hydrogen or methyl; R³ is hydrogen or methyl; R⁴ is hydrogen or methyl; R⁵, R⁶, R⁷ and R⁸ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) --wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)--wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; and (13) -- N(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined; and R⁹ is hydrogen or methyl. 